Spark-plug



I. H. COLLINS.

SPARK PLUG.A

APPLICATION FILED MAR. 8| I9|9 Patented Nov. 9, 1920.

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` combustion of the gases,

UNITED STATES PATENT OFFICE.

SPLBK- PLUG.

Y '0 all whom it 'may concern:

Be it known that I, JAMES H. COLLINS, a citizen of the United Statesresiding at Harrisburg, in the county of bauphin and State ofPennsylvania, have invented certain new and useful Improvements inSpark- Plugs, of which the following is a specilication.

The object of this invention is to provide a sparlcplug of improveddesign for internal combustion engines, and adapted to overcome thedefects commonl experienced in other plugs, and resultinglyf recognizedby increased efiiciency thereover.

After exhaustive study upon the subject of spark-plug construction andperformance, certain unfailing rules have been observed regarding theirgeneral characteristics. With a given supply of electric current, andthe same spark-gap is used, the spark of a plug having a single gapbetween a pair of electrodes is fatter, or of more intense heat thanwhere a plurality of gaps is used.

But with a single gap, it is obvious that, as a result of anything essthan a complete a deposit occurs and tendseventually to bridge said gap,whereas, other factors being equal, the same deposit will generally takemuch longer to short circuit a multiplicity, care being exercised nottoincrease the number of the same unreasonably, and thereby develop aninfinite number of sparks but with greatlydecreased ability to ignitethe usual gaseous mixture. i

These are by no means the only rules which must be recognized asgoverning the details of spark-plug construction, but they will suliicefor purposes of illustrating the care which must be exercised indesigning any new departure in this class of devices. And as a result oftakin construction hereina ter described in detail` has been developed,and the same has been proved to insure dependable operation under themost 'exacting conditions presented by commercialservidt.

Thuii, object of the invention is to provide a' siizrlnplug adapted to'produce hot fat .s 'arks simultaneously across a plurality ofsparkggaps; to provide means for adjusting the istances across all ofsaid gaps simultaneously; to provide a positive electrode so constructedas to disrupt the s ark discharges therefrom in order to cause t em topenetrate and ignite the gaseous Speclcaton ot Letters Patent.

Application illcd March 8, 1919.

them collectively, the

Patented Nov. 9, 1920. semi no. 281,345.

mixtures in a cylinder with greater certainty; to provide a constructionoperative to permit the porcelain part or parts of the improvedspark-plug to yield, as may be desired, to the ex lesions within acylinder instead of being rigidly held in position and thereby subjectedto fracturing stresses; and to provide with all acme of simplicity inthe construction of the improved spark-plug its various details.

With these and other objectsin view, the invention consists in noveldetails both in construction and operation, hereinafter fully broughtout in the following description, when read in conjunction with theaccompanying drawings, in which fi re 1 is an elevation of the preferredembo iment of the invention; Fig. 2 is a vertical diametrical section ofthe same; Fig. 3 is a bottom plan view of the same; Fig. 4 is a sectionon the line 4 4 of Fig. 2; and Fig. 5 is an enlarged detail diametricalsection of the central e ectrede-head.

Referring to the drawings, a metal cylinder 1 is provided, upon one endwith externa] screw-threads 2, while its outer end portion 3 is providedexternally with screwthreads adapted to engage corresponding threadswithin an aperture in the cylinder of an internal combustion engine (notshown), while connecting the main and reduced portions of said metalcylinder is a Vplain wall surface 4, functioning as hereinafterdescribed.

Within the larger l and immediately a( ortion of the cylinder jacent tothe surfe-ceti is an annular gasket 5, preferably made ofnon-inflammable fibrous material such as asbestos, and u on which inturn is laced an annular gas et 6 of relatively so ma teri'al such ascopper. The porcelain member 7, of substantially the saine diameter asthe member 1 is inserted thereintc and with a reduced end portion 8extending into the reduced portion 3 of said member, while the saidorcelain is provided thro h its enlarged portion with a centrallypositioned bore 9, terminating in a larger similarly ositioned b'ore 10passing through its reuced portion.

Extending through the bore 9 in the porcelain member 6 is a threadedstem 11 carr in a nut 12, which, cooperating with t e sidges of bore 10,revolves with respect to the said stem upon turni the latter, and thusoperates to shift sai stem longitudinally through the said bores. Theinner end por tion of the said stem (considering a sparkplug as whenpositioned o eratively with respect to an engine cylinder? comprises oneof the electrodes separated by a gap, between which sparks jump for thepurpose of igniting the explosive gases within the cylinder of aninternal combustion engine in the usual manner.

Surrounding the stem 11, and abutting against the larger end of theporcelain member 7, is a loosely mounted washer 13, against which ispressed a radially outwardly flanged portion 14 of a non-inflammablecylinder 15, closely yet slidabl surrounding t e stemand in turn surrouned by a cylindrical portion 16 of a second non-inflanr mable memberprovided with a radially outwardly extending annular flange 17, oppositely positioned with respect to the flange 14, and between whichflanges extends a compression coil-spring 18 surroundingr thetelescoping portions 14 and 1G ol the re# `second electrode passingcentrally between spective non-inflammable members.

The major portion of the spring and copcrating members thus describedarepositioned within the enlarged portion 19 of a bore 20, extendingrespectively through an enlarged section 21and a reduced section 22 of asecond porcelain-member, said sections of this member being connected ba radially extending external surface Q3 orming an annular shoulderagainst which bears uniformly an annular washer 24 of relatively softmaterial such as copper. lVith the inner parts of the device constructedand positioned as thus described, an internally threaded cap 25,provided with a central bore 2G, is then slipped over the secondporcelain member and screwed firmly upon the threaded portion 2 of themetal cylinder 1.

Upon the opposite or outer free end of the stcm 11 is positioned alock-nut 27, while adjacent thereto said stem is provided with a knurledbinding-nut 28, for the purpose of rcmovabl yet firmly attaching to saidstem the usualv electric conductor. Tn order to adjust the longitudinalposition of the stem forming a part of this improved spark-plug, thebinding-nut being loose, the lock-nut 2 is loosened, and said stemrevolved in thc drection desired for the purposc of shifting itselectrode section into operative position with respect to thc reducedportion Il of the member l. which reduced portion forms a. secondclcctrodc. or out of this position it is free from said reduced portionfor thc purpose of cleaning both electrodes.

The central electrode, which is the inner end portion of the stem 11, ismade in such manner as to comprise two spaced disks 29 and 30, integralwith said stem and forming at first radially extending flanges lying inparallel planes. However, these spaced disks are scalloped at spacedintervals ll in order to form between adjacent scallops blunt dischargepoints 32.

The oppositely disposed points of each pair are thcn brought toward eachother as clearly shown in 'I1 ig. 5, so that the pointed sections,together with that part of the stem 11 connecting them, coperate to formin cross-section a horse-shoe shape, after which the extremities of saidpoints are turned off concentrically with said stem, so that the outersurfaces of the points of each pair are in alinem'ent with each other,and thereby at all times equi-distant from the adjacent portion of theelectrode section of the member l, as Well as insuring the distancesbeing equal between each pair of said points and said portion of thesecond electrode.

In setting the position of the central electrode longitudinally withrespect to the seeand or surrounding electrode, care is taken to soadj/ust the former as to insure the plane of the peripheral surfaceextremity of the the points of each ofthe pairs of points upon saidcentral electrode, because of the fact that electric sparks universallytend to jump f'rom and toward the sharpest edges or points o'fyneighboring members of opposite polaity. Thus1 while the dischargepoints of the disk 25) are actually within the reduced electrode portionof the member l, sparks jump from said points to the inner edgel of thesurrounding electrode, toward which edge sparks also jump from thepointed lateral extremities of the disk 3U, forming thereby a continuousspark discharge from the points of each pair to the neighboring portionof a second electrode, and addiY tionally, while the actual theory of'thc discharge may not be fully understood at this time, it is believedthat the pcculiar character of the discharge is at least partially ducto the discharges from the disk 2f) to thc nearest edge of the electrodeIl being disrupted or repelled to a certain extent by thc charge of thesame polarity upon the neighboring points of thc disk 'lfl. ."limilarly`it appears that a discharge from the points of the disk 30 is arcedoutwardlyr and possesses an increased fiery characteristic, hccausc ofthc. nearness of the respective oppositcly positioned points of the disk2!) ol' thc same polarity.

Thus, this construction effects a discharge from the central to thcIsurrounding clcctrode of a considerablyl difl'crcnt cluiructcr, thccentral electrode haring lhc form of a continuous disk, a geur-shapeddisk pro vided with sawtccth. or a central electrode comprising onc ormore discharge points cxtcnding radially therefrom, such as occurs inmany wcllknown types of devices of this character.

Having thus described my invention,

what I claim and desire to protect by Letters Patent of the UnitedStates is 1. A spark-plng, comprising a casing, a porcelain seatedwithin saidcasing, a sec4 ond porcelain within and normally seatedagainst said casing, an electrode extending through said poreelains andnormally fixed with respect to said first portion, and resilient meansbetween Asaid porcelains, operative to permit said second porcelain toyield in accordance with explosions within a cylinder of an internalcombustion en gine, and to move with respect to said electrede.

2. A spark-plug, comprising a metal casing forming one electrode, aporcelain seal seated within said casing, a second porcelain within saidcasing, a second electrode supported by said porcelain, and resilientmeans between said porcelains, operative to permit said second porcelainto yield in accordance with explosions within a cylinder of an internalcombustion engine and independeutly of said second electrode.

3. A spark-plug, comprising an electrode having a pair of concentricdisks, the peripheral portions of said disks being sepa rated a lessdistance than. their central portions.

4. A spark-plug, comprising an electrode having a pair ofa concentricdisks slightly7 scalloped to provide circumferentially spaced radiallyextending projections co1'- respondingly positioned upon each of saiddisks, and the extremities of said projec tions o f each pair beingcloser together than the central portions ofsaid disks.

5. A spark-plug, comprising a metal casing having an annular edgeportion forming one electrode, and a second electrode comprisino twospaced disks uniformly and respectively spaced away from the edgeportion of said first electrode.

6. A spark-plug, comprising a metal easing having an Vannular edgeportion forming one electrode, and a second electrode. positionedcentrally within said first electrode, and comprising spaced diskshaving spaced peripheral projecting portions spaced an ecpial distancefrom the edge portion of said first electrode and the corres|mndingprojection.

7. ln a sparlcplug. an electrode comprising a stem provided with spacedflanges, each of said flangesI Vscalloped at lintervals. to provideintermediate substantially radial projections oppositely disposed uponsaid flanges.

f-l. In a spark-plug. an electrode comprising a stem provided withspaced flanges,

each of said flanges scalloped at intervals to provide intermediatesubstantially radial projections oppositely disposed upon said flanges,the projections upon each of said flanges being directed toward thecorresponding projections upon the other of said flanges. y

9. In a spark-plug, an electrode comprising a stem provided with spacedflanges, each of said flanges scalloped at intervals to provideintermediate substantially radial projections oppositely disposed uponsaid flanges, the project-ions upon each of said` flanges being directedtoward the corresponding projections u on the other of said flanges, andthe radia ly outer surfaces of said projections being in alinement andconcentric with said stem.

10. In a spark-plug, an electrode comprising a stem provided with spacedflanges, each of said flanges scalloped at intervals to provideintermediate substantially radial projections oppositcly disposed uponsaid flanges, and a surrounding electrode surface positioned so that theplane of said surface is substantially perpendicular to the axis of saidstem and intersects said stem substantially midway between said flanges.

11. In a spark-plug, an electrode comprising a stem provided with spacedflanges, each of said flanges scalloped at intervals to provideintermediate substantially radial projections oppositely disposed uponsaid flanges, the projections upon each of said flanges being directedtoward the corresponding projections upon the other of said flanges` anda surrounding electrode surface positioned so that the plane of saidsurface is substantially perpendicular to the axis of said stein andintersects said stem substantially midway between said flanges.

1&2. In a spark-plug` an electrode comprising a stem provided withspaced flanges, each of said flanges scallo ed at intervals to provide.intermediate su :stantially radial projections oppositely disposed uponsaid flanges` the projections upon each of said flanges heilig directedtoward the corresponding projections upon the other of said flanges` theradially outer surfaces of said projections being in alinement andconcentric with said stem, and n surrounding electrode surfacepositioned so that the plane of said surface is substantiallyperpendicular to the axis of said stem and intersects said stemsubstantially mid-way between said flanges.

In testimony whereof I have affixed( my signature.

JAMES I-I. COLLINS.

